title: Use of an extruder for pre-mixing enhances xylanase action on wheat bran at low water content.
abstract: The aim of the work was to test the hypothesis that at low water content enzyme action on biomass is enhanced when the raw material is in the form of a continuous mass instead of powder/granular form. Effects of two pre-mixing methods, blade-mixing and extrusion, on xylanase action were studied during stationary incubation of wheat bran of different particle sizes, also in comparison with incubation at high water content with continuous stirring. The use of an extruder enhanced arabinoxylan (AX) solubilisation at low water content (<54%), as compared to blade-mixing. AX solubilisation was highest in the high-water stirring treatment, but based on molecular weight, xylanase action on solubilised AX was similar as in the extrusion-aided process. Pre-mixing by extrusion enabled efficient enzyme action at low water content without the requirement for continuous mixing, probably due to the enhanced diffusion by the formation of a continuous mass in the extruder.
authors.affiliation: VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo, Finland. Electronic address: outi.santala@vtt.fi.
authors.forename: Outi
authors.initials: O
authors.lastname: Santala
authors.forename: Emilia
authors.initials: E
authors.lastname: Nordlund
authors.forename: Kaisa
authors.initials: K
authors.lastname: Poutanen
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods*; D004043:Dietary Fiber / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D000431:Ethanol / Q000737:chemistry; D008970:Molecular Weight; D010316:Particle Size; D012995:Solubility; D014867:Water / Q000494:pharmacology*; D014990:Xylans / Q000378:metabolism
chemical_list: D004043:Dietary Fiber; D014990:Xylans; D014867:Water; D000431:Ethanol; C085118:arabinoxylan; D043364:Endo-1,4-beta Xylanases
keywords: Enzymatic hydrolysis; High solids; Mixing; Particle size; Wheat bran